If you don't talk to Miranda on those 3 occations, especially if you don't tell her about Kai L..... she won't survive Horizon. You are in a very delicate Situation here. But luckily for you:

'If you break off a romance with her during Mass Effect 3 she will also die, regardless of whether you did both her loyalty mission and warned her of Kai Leng. Breaking off a romance during Mass Effect 2, even at the very end before importing the save, will not result in her death. A romanced Miranda will also survive if you have "locked in" another romance before the apartment scene - only an explicit on-camera breakup leads to death. '

Source: Priority Horizon guide in this very Wikia......

So you can talk to Miranda and all day.... as soon as you lock in on beloved Liara on the Pressidium Commons asap... Miri won't hassle you about it like.... well Ashley would.